Nonsmudging transfer sheet



Jan. 30, 1940.' J. BJQRKSTEN 'ET Al. y 2,188,590

NONSMUDGING TRANSFER SHEET;`

Filed Feb. 4. 1938 ...Patented Jan. 30, 1940 i .o

UNITED iSTATES PATENT OFFICE I Incorporated, Ghicago, Ill.,` acorporation of West Virginia/f' .-1 imitation rebusry 4.1938, serial No.188,107 schim. (ci. zzz-2s) This invention relates to transfer sheets,yand of the keys of a typewriter as shown in Fig. 2, more particularlyto nonsmudging impression portions of the resin and the underlyingcomtype transfer sheets. It includes transfer sheets position will bedetached together from the coatsuch as carbon paper, typewriter ribbon,and ing to form an imprint on the contacting sheet,

5 the like, which are coated with a composition as shown in Fig. 3, andwill be firmly secured to v5 which is transferable to a contactingsurface by Said sheet by means 0f the resin. v the application ofpressure or impact such as may It has been discovered that natural andsynbe produced by a pencil or the keys of a typethetic resins which areof high enough molecuwriter. These impression type transfer sheets larweight to be frangible nonsmearing solids but l0 may generally bedivided into three classes; (l) of not such high molecular weight astoform 10 transfer sheets such as ordinary carbon paper, tough,self-sustaining lms of the nature of rub- `Which contain a pigment; (2)transfer sheets ber or nitrocellulose are in general most suitable suchas hectograph carbon paper which contain yfor forming the smudge PrOOffilm Coating 0f this a soluble dye, and (3) .tranfer sheets such asinvention. 18 printing process carbon paper, which contain a However,these resins also must be soluble in 5 waxy or oily ink absorbentmaterial, solvents which are not solvents for the under- An object ofthis invention is to provide e lying transfer composition, and notsoluble in smudge proof impression type transfer sheet any of theconstituents of the underlying transwhich is capable of forming clearand adherent fer COmPOSitiOn- 20 impressions. When the transfercomposition, for example, 20

Another object is to provide a smudgeproof consists mainly of an alcoholor water soluble transfer sheet of the type which contains a soldye, theresin to be used for the protective coatuble dye, and is suitable forspirit process or ing should be insoluble in water or alcohol. Forheotograph use. example, if the dye is crystal or methyl violet or Afurther object is to provide e, smudgeproof fuchsine, then the followingsolvents would be 25 transfer sheet of the type which contains waxysuitable for application of the coating resin: caror oily ink absorbentmaterial, and which is suit.. bon tetrachloride, benzol, isopropylether.

able for making impressions which may be re- Particularly suitable asmaterials for protecinked, tive coatings or transfer sheets containingwater 8. other-.objects and features of this invention or a1coh01soluble dyestuffs. arethe alkyd resins. 3 will become apparent es thefollowing detailed the highly chlorinated rubber resins, the soliddescription progresses, reference being had to cumaroneindene resins`and cyclized rubber resins l the accompanying drawing, in which;obtained from rubber by reacting the rubber in Fig, 1 is an enlargedsectional view of the solution with `an amphoteric metal halide or I5smudgeproof transfer sheet, chlorostannic acid and isolating the endproduct. 35

Fig. 2 is a detailed sectional view showing the To prevent excessivehardening of the applied invention applied to typewriter operation.coating, it is generallyadvisable to include in the Fig. 3 is anenlarged detail sectional view of an coating solution small amounts ofplasticizers.A impression produced from the transfer sheet of Forexample. Castor Oil. Stealc Reid. Dara-m11 Wax. 40 Fig. 1 cna mastersheet. or any other non-drying substance which pre- 40 Referring to thedrawing in which an embodivent the resinous coating from becoming tooment of the invention is shown, reference charhard. acter l designates abase sheet such as tissue Examples of suitable coating formula. aregiven paper or other sheet material having thereon a below:

ltransfer coating 2 of a soluble dye or of an ole- 1 Preferred formulae45 aginous composition depending on the application of the invention,and having a-smudge proof Femm wmptm layer 3 over said coating 2.

In the preferred embodiment of the invention 'l 2V 3 n 5o the smudgeproof layer 3 comprises a reslmpreierably in combination with aplasticizer, and is mzegfxt, bis' 35 LB v. g1g of such friability,strength, and adhesive power Chmn glia--h-l-H -r-L 0.2 0-2 0.2 that whenthe transfer sheet is used with a cone'oivent{2,'e c n 98 ';g' tactingsheet l for duplicating in the usual pres# ISO propyiether 50 sure orimpact manner. as for example by means I l 55 In the above formulaePetrex No. 1 is the trade name of a product of Hercules Powder Co. Moreparticularly, it is a modified alkyd resin made from polybasic acids ofthe alicyclic series.'

Other suitable formulae Resin 1.8 1 6.2 Dulux R-C-l 2 Carbontetrachloride 98 99 98 98 98 47 Solvent Femme 98 98 Iso propyl ether Inthe above formulae the following trade names are used.

Amberlac D-96--Made by Resinous Products & Chemical Company. Meltingrange -90 C.-a modified alkyde resin-a light amber solid resin.

Neville R-10 Hard Resin-Made by Neville Co.-Coumarone indene resin-lightamber solid resin. Melting range 13D-150 C.

Dulux R-C-l-Made by E. I. du Pont deber in solution with an amphotericmetal halideA or chlorstannic acid, and isolating the resulting cyclizedrubber. A brittle resin. Sometimes called a condensation derivative ofrubber, particularly in the Goodyear patents. See viz. U. S. Patent2,052,391.

Method of application of the above formulae:

Any of the above preparations may be applied in any convenient manner sothat after evaporation of the solvent a thin lm remains covering thematerial treated. Generally, it is preferred to dip the carbon sheet,ribbon, etc., into the solution, withdraw it after a few seconds and todry it by means known to the art. In a wann air current the drying iswell-nigh instantaneous.

The resinous protective coatings are particularly suitable fordye-carrying impression type transfer sheets and such resin protectedtransfer sheets oier some very important advantages in liquid or directprocess duplication. In that method a dye carrying master" sheet isprepared by typing or writing on a sheet of suitable paper against a dyecarrying impression yielding sheet, so that a design in reverse isproduced on the back of the master sheet. This master sheet is then bymechanical means repeatedly brought to contact copy papers, which havebeen previously moistened with a volatile dye-solvent, so that dye fromthe impressions on the master sheet is transferred to the solventmoistened copy sheets, in such manner that copies are produced of thematter written on the master sheet. By this process several hundredreadable copies may be obtained, but after -250. copies the master sheetbecomes moistened with dye solvent, which partially dissolves some ofthe dye at the base of the dye carrying impressions on the master sheet,causing these to spread out ,and smudge, whereby the copies are. greatlyimpaired.

This is particularly objectionable when a comparatively less volatilesolvent is used, such as for example water. to which may have been addeda surface tension reducing agent to assist in spreading of the solvent.

However, when a protective coating is employed, according to thisinvention, the base of the dye carrying impression on the master sheetconsists of the material of this protective coating as shown in Fig. 3;Since this coating material would generally be insoluble in all solventsused or contemplated for liquid process duplication, it prevents accessof the solvent to the dye,

v and consequently also prevents such deterioration of the masterimprint as usually occurs after 150-250 copies due to deterioration ofthe dye.

Resinous protective coatings may also be applied to other impressiontype transfer sheets than those carrying dye stuffs. However, when thetransfer composition contains an oleaginous or waxy material, it isnecessary to use resins which are soluble in a solvent which does notappreciably dissolve or soften the oleaginous or waxy materials. Onetype of transfer sheet which is particularly important at the presentdate is the so-called printing process carbon paper. This is a carbonpaper which contains no pigment and which may or may not contain a dyestuff. Its essential ingredient is a soft oily or waxy material which istransferable to a contacting surface by the application of pressure or vimpact such as may be produced by a pencil or a typewriter, and whichgives an imprint on the contacting surface which is adherent and highlyink-absorbent. These printing process transfer sheets, however, are sosensitive to pressure and impact that they tend to give imprints fromother causes than the impact of the keys of the typewriter. Such othercauses are, for example, a casual pressure from the operator's hands ora. pressure from the roller of the typewriter. When the copy obtained isused as means of ink transfer in a printing process all suchnon-intentional impressions will also become inked, and cause ink orsmudge on the copy sheets.

As far as is known, printing process carbon papers have not hithertobeen made which.are substantially smudge proof.

In accordance with this invention printing process carbon papers arecoated with a protective coating of a resin which is applied dissolvedin a solvent which does not dissolve the oleaginous material of thetransfer compositions.

'Ihe following example will illustrate the invention as applied toprinting process carbon paper:

In coating the printing process transfer sheet a .2% solution of shellacin ethyl alcohol is spread over the transfer sheet, and the solventsubsequently evaporated at a temperature lower than the melting point ofthe transfer coating.

While there have been shown and described certain forms of theinvention, it is to be understood that it is capable of manymodifications. Changes, therefore, may be made without departing fromthe spirit and scope of the invention as described in the appendedclaims, in which it is the intention to claim all novelty inherent inthe invention as broadly as possible, in view of the prior art.

We claim:

1. ,A transfer medium adapted for use with a pressure or impactinstrumentality such as a pencil or the keys of a typewriterv comprisinga base coated with a pressure or impact transferable composition, and ailm essentially com.

- prising resin coated on said transfer composition,

said nlm being of such character that it will break and be transferredto a contacting sheet with the transfer composition when pressure orimpact is applied to the transfer sheet by a pencil or the keys of atypewriter in the usual manner, of such adhesive character that it willadhere to the contacting sheet and to said base transfer composition, ofsuch solubility that it will dissolve in solvents which are not solventsfor the base transfercomposition.

2. A transfer medium adapted for use with a pressure or impactinstrumentality such as a. pencil or the keys of a typewriter comprisinga base coated with a pressure or impact transferable composition, and afilm essentially comprising resin coated on said transfer compositionAsaid film being of such character that it will break and -be transferredto a contacting sheet with the transfer composition when pressure orimpact is applied to the transfer sheet by a pencil or the keys of atypewriter in the usual manner,

of such adhesive character that it will adhere to the contacting sheetand to said base transfer composition, of such solubility that it willdissolve in solvents which are not solvents for the base transfercomposition, the resin of said lm being of the class of natural andsynthetic resins which are of sufficiently high molecular weight to befrangible non-smearing solids.

3. A transfer medium adapted for use with a pressure or impactinstrumentality such as a pencil or the keys of a typewriter comprisinga base coated with a pressure or impact transferable composition and apressure or impact transferable film essentially comprising an alkydresin, coated on said transfer composition.

4. A transfer medium adapted for use with a pressure or impactinstrumentality such as a pencil or the keys of a typewriter comprisinga base coated with a pressure or impact transferable composition and apressure or impact transferable lm essentially comprising a chlorinatedrubber coated on said transfer composition.

5. A transfer medium adapted for use with a pressure or impactinstrumentality such as a pencil or the keys of a typewriter comprisinga -base coated with a pressure or impact transferable composition and apressure or impact transferable lm essentially comprising a condensationderivative of rubber coated on said transfer composition.

6. A transfer medium adapted for use with a pressure or impactinstrumentality such as a pencil or the keys of a typewriter comprisinga base coated with a pressure or impact transferable composition,containing soluble dye, and a film essentially comprising resin coatedon said transfer composition, said nlm being of such character that itwill break and be transferred to a contacting sheet with the transfercomposition when pressure or impact is applied in the usual manner, ofsuch adhesive character that it will adhereto the contacting sheet andto said base transfer composition, of such solubility that it willdissolve in solvents which are not solvents for the base transfercomposition.

7. A transfer medium adapted for use with a pressure or impactinstrumentality such as a pencil or thev keys of a typewriter to producereinkable impressionpn a contacting sheet, said transfer mediumcomprising a base coated with a pressure or yimpact transferablecomposition containing a waxy or oily ink absorbent material, and a filmessentially comprising resin coated on said transfer composition, saidfilm being of such character that it will break and be transferred to acontacting sheet With-the transfer composition when pressure or impactis applied in the usual manner, of such adhesive character that it willadhere to the -contacting sheet and to said base transfer composition,of such solubility that it will dissolve in solvents which are notsolvents for the base transfer composition.

8. A transfer sheet designed for use in a typewriter to producereinkable oleaginous impressions on a contacting sheet, said transfersheet having a substantially pigment free oleaginous coating and apressire or impact transferable coating on said first coating comprisingshellac.

9. A transfer medium adapted for use with a pressure or impactinstrumentality such as a pencil or the keys of a typewriter to producereinkabie impressions on a contacting sheet, said transfer mediumcomprising a base coated with a pressure or impact transferablecomposition containing a waxy or oily ink absorbent material, and a filmlayer comprising primarily a resin and a plasticizer on said transfercomposition, the resin being present in such amount as to securesubstantially increased adhesiveness as compared to the oily oroleaginous material of the first coating, and the plasticizer beingpresent in such amount as to render the second coating transferable withthe first coating by pressure or impact.

JOHAN BJORKSTEN. WILLIAM J. CHAMPION

